A Whangaparaoa mother has reportedly kept her seven-year-old child home from school to stop him from acting in a nativity scene.
She told Stuff at the weekend it was "out of line" for Stanmore Bay School - meant to be secular - to put a Biblical slant on Christmas activities.
Massey University history professor Peter Lineham told The AM Show on Monday reactions like this are not uncommon nowadays.
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"I think some craziness has hit, and it must be the Christmas season, that we're all acting madly. This happens every year about this time of year."
Prof Lineham, an expert in religious studies, said teaching about the nativity wouldn't "pollute [their] infant minds".
He said it's getting more difficult to teach in a country that is growing more secular.
"Imagine being a teacher in a school where you do a single step and there's a row of parents who are rushing to protest, and you can't refer to any history that may offend somebody."
Prof Lineham said the birth of a historical figure named Jesus in Palestine is an "indisputable fact", and questioned how anyone could discuss Christmas if "you can't talk about the things it was based on".
"You would have to ban almost all teaching of a very wide range of social and cultural matters" to keep everyone happy, he said.
But AM Show newsreader Ingrid Hipkiss said not enough emphasis is placed on the stories of Christmas being exactly that - just stories.
"I do think that there is not enough made of saying 'this is one story, here's another story and here's another story'."
She said there needs to be options of religious education, rather than one exclusive narrative.
But Prof Lineham believes a society that moves away from Christianity will struggle to maintain its values and morals.
"Will a secular society that doesn't have a basis to draw on those values be able to maintain them?"